pub fn odd_fibnacci_sum(threshold: u32) -> u32 {
    // TODO: 这里写逻辑
    let mut a = 0;
    let mut b = 1;
    let mut ans = 0;
    while b < threshold {
        // 判断当前为奇数
        if b % 2 != 0 { 
            ans += b;
        }
        let tmp = b;
        b = a + b;
        a = tmp;
    }
    ans
}
